TWI485921B - A binder for lithium ion rechargeable battery cells - Google Patents

Description

Adhesive for lithium ion rechargeable battery cells

This invention relates to lithium ion rechargeable battery cells, and more particularly to bonding agents for use in such batteries.

Lithium-ion rechargeable battery cells currently use carbon/graphite based anodes. A basic composition of a conventional lithium ion rechargeable battery cell including a graphite-based anode electrode is shown in FIG. The battery pack can include a single battery, but can also include more than one battery.

The battery cells typically include a copper current collector 10 for the anode and an aluminum current collector 12 for the cathode, which may be externally connected to a load or source of charge when appropriate. It should be noted that the terms 〝 anode 〝 and 〝 cathode 〞 are used in the description of the present invention because those terms are known in the context of a battery pack configured across a load, that is, the term 〝 anode 〞 represents the negative electrode of the battery pack and the term The cathode 〞 represents the anode of the battery pack. A graphite-based composite anode layer 14 covers the current collector 10 and a composite cathode layer 16 based on a lithium-containing metal oxide covers the current collector 12. The porous plastic spacer or separator 20 is provided between the graphite-based composite anode layer 14 and the lithium-containing metal oxide-based composite cathode layer 16: the liquid electrolyte material is dispersed in the porous plastic spacer or Within the separator 20, the composite anode layer 14, and the composite cathode layer 16. In some examples, the porous plastic spacer or separator 20 can be replaced with a polymer electrolyte material, and in such examples, the polymer electrolyte material is present within both the composite anode layer 14 and the composite cathode layer 16.

When the battery cell is fully charged, lithium has been transported from the lithium-containing metal oxide in the cathode to the graphite-based anode, where lithium is inserted by reaction with graphite to produce lithium carbon compounds. Typically LiC ₆ . Graphite is an electrochemically active material in a composite anode layer having a maximum capacity of 372 milliampere hours per gram.

It is well known that rhodium can be used in place of graphite as the active anode material (see, for example, Insertion Electrode Materials for Rechargeable Lithium Batteries, M. Winter, JO Besenhard, ME Spahr, and P. Novak in Adv. Mater. 1998, 10, No. 10). It is generally believed that when ruthenium is used as the active anode material in a lithium ion rechargeable battery, ruthenium can provide a significantly higher capacity than the graphite currently used. When ruthenium is converted to the compound Li ₂₁ Si ₅ by reaction with lithium in an electrochemical cell, ruthenium has a theoretical maximum capacity of 4,200 mAh/g, which is higher than the maximum capacity of graphite. Therefore, if graphite is replaced by ruthenium in a lithium rechargeable battery pack, a substantially increased storage energy per unit mass and per unit volume can be achieved.

In a lithium ion rechargeable battery cell using a graphite-based anode, graphite has a fine powder form, and the particles are fixed together by a binder. Polyvinylidene fluoride (PVDF) and styrene butadiene rubber (SBR) are the most commonly used binders in graphite anodes, but other binders have been suggested. For example, US-5660948 discloses the following binders for lithium ion batteries. Among the carbon anodes: ethylene-propylene diene third monomer (termonomer), PVDF, ethylene-acrylic acid copolymer and ethylene vinyl acetate copolymer.

US-6,399,246 teaches that poly(acrylic acid) does not provide good adhesive properties in the graphite anode of a lithium ion battery cell and requires the use of a polypropylene guanamine binder.

US-6620547 discloses a lithium secondary battery having a carbon anode into which lithium can be inserted and a cathode system formed from a transition metal fixed with a matrix polymer. The polymer used has an affinity for the transition metal ion so the plasma is immobilized on the polymer chain. The polymer may be selected from a wide variety of materials such as polyacrylates, poly(acrylic acid), polymethyl methacrylate, poly(vinylpyrrolidone), polyacrylonitrile, poly(vinylidene fluoride), and poly(chlorine). Ethylene).

No. 5,260,148 discloses a lithium secondary electrode having an anode formed from a lithium compound held together by a binder, which may be starch, carboxymethyl cellulose (CMC), diethyl cellulose, hydroxy Propyl cellulose, ethylene glycol, poly(acrylic acid), polytetrafluoroethylene, and poly(vinylidene fluoride).

The binders (PVDF and SBR) most commonly used in graphite anodes for lithium-ion batteries do not cohesively bond the ruthenium electrode materials in the ruthenium-based anodes through a continuous charge cycle, and believe this This is due to the relatively large volume change associated with the removal and removal of lithium ions from the germanium material during the charging and discharging phases of the battery. The volume change is much larger than the volume change in the corresponding graphite anode and can cause the individual tantalum particles to never again establish electrical contact with each other and with the current collector as the tantalum anode shrinks due to lithium ion removal during discharge.

An alternative binder that has been proposed for the system is sodium carboxymethyl cellulose (NaCMC). Na-CMC has a suitable function as a binder when used in combination with high purity bismuth (the type used to fabricate integrated circuit (IC) Si-wafers). However, this is very expensive. When a relatively inexpensive lower grade crucible is used, there are trace impurities that are not chemically compatible with the binder solution and which cause a decrease in the viscosity of the crucible/binder mixture. Thus, the resulting coating does not retain sufficient contact with the current collector to perform any more than a limited number of discharge/charge cycles before losing battery capacity to maintain charging.

Journal of Applied Electrochemistry (2006) 36: 1099-1104 discloses the use of an acrylic adhesive as a binder for the anode of a Li-ion battery. The anode material is a Si/C composite, so it has a lower volume change than an electrode in which the anode is a separate Si. In addition to the adhesive referred to as product LA132, it is believed that the composition is a mixture of acrylonitrile and butadiene in methyl ethyl ketone, ethyl acetate and toluene, and the nature of the acrylic adhesive is not disclosed.

J Power Sources, 161 (2006), 612-616 discloses a carbon anode for a lithium ion battery, which also contains NaCMC as a thickener and SBR as a binder. PAA (poly(acrylic acid)) was added as a surface active dispersant.

J Power Sources, 173 (2007), 518-521 proposes a problem in the use of a propylene carbonate solvent/electrolyte for a graphite electrode for a Li-ion battery because propylene carbonate is inserted into the graphite electrode during charging/discharging, causing a solvent Decomposition and graphite stripping. Solve this problem by adding a PAA.

It is an object of the present invention to find a binder which satisfactorily bonds together various particulate germanium materials in the electrodes of a rechargeable lithium ion battery that has undergone many discharge/charge cycles before losing battery capacity to maintain charging, and In particular, particles made from relatively inexpensive crucibles of lower grades are subject to large volume changes associated with the incorporation of lithium ions into and/or out of the crucible material during such cycles.

Surprisingly, it was found that poly(acrylic acid) (PAA) is a good binder for the particulate ruthenium material in the electrode of a rechargeable lithium ion battery, regardless of the large volume change associated with the discharge/charge cycle, and it can be combined with high purity. Both hydrazine (99.90% purity or above) and lower purity hydrazine (less than 99.90% purity or less) are used.

A first aspect of the present invention provides an electrode for a lithium ion rechargeable battery cell comprising:

- current collector, and

a cohesive material comprising ruthenium as an active material and a polymeric binder, characterized in that the polymerizable binder is a homopolymer or a copolymer of one or more monomers selected from the group consisting of the following Groups: acrylic acid, 3-butenoic acid, 2-methacrylic acid, 2-pentenoic acid, 2,3-dimethacrylic acid, 3,3-dimethacrylic acid, trans-butenedioic acid, Cis-butenedioic acid and itaconic acid and, if desired, an alkali metal salt thereof, wherein cerium comprises from 20 to 100% of active material, and wherein the binder is mixed with cerium to form a cohesive material which is attached to the current The collector maintains the cohesive material in electrical contact with the current collector.

The binder is suitably in the form of a homopolymer or a copolymer. Typical copolymers include alternating copolymers, block copolymers, periodic copolymers, and statistical copolymers. These polymers can be formed from the reaction of polymer blocks formed from different combinations of the above-described monomer units and also formed from such monomer units.

Suitable alkali metal salts of such polymers include the salts of lithium, sodium and potassium. The poly(acrylic acid) alkali metal salts are preferred, especially for their sodium and lithium salts.

As described above, although poly(acrylic acid) is known as an alternative binder for PVDF and SBR binders which are more commonly used in graphite electrodes for lithium ion batteries, charging/discharging using ruthenium as an active material in an electrode is known. The volume change that occurs during the cycle is greater than when graphite is used as the active material. In addition, US-6,399,246 teaches that poly(acrylic acid) does not provide good adhesive (bonding) properties to graphite anode materials in lithium ion batteries.

The inventors have found that poly(acrylic acid) can effectively bond ruthenium as an active material in an electrode of a lithium ion battery, and thus is surprisingly and unexpectedly at the same time.

Compared with NaCMC, the acrylic adhesive of the present invention can be used with all grades of ruthenium in Li-ion electrodes and can have stable cycle life performance, while also overcoming the need for NaCMC binders to be present in lower cost grades. The potential instability of the impurity element.

In addition to PAA, other polymeric acrylic acid derivatives can be used as the binder, as set forth in Table 1, and mixtures of such binders can also be used.

Copolymers of one or more of the above polymers with each other or with other vinyl-containing monomers (for example, vinyl acetate) such as poly(acrylamide-co-acrylic acid) may also be used.

A wide variety of molecular weight poly(acrylic acid) or poly(methacrylic acid) or derivatives thereof can be used, for example, preferred PAA molecular weight systems are greater than 50,000 (e.g., 450,000 molecular weight) and also greater than 1,000,000 (e.g., 1, 250,000).

The crucible in the electrode can be in any suitable form. Niobium is suitably provided in the form of particles, fibers, flakes, columnar or ribbon-like particles (as described in WO 2008/139157) or in the form of columnar particles. Fibers can be made using the techniques disclosed in WO 2007/083152, WO 2007/083155, and WO 2009/010758. The columnar particles are ruthenium particles, and the columns thereon have been etched using the techniques described above, as disclosed in WO 2009/010758.

The ruthenium is preferably a particle, a fiber or a columnar particle or a mixture thereof. The ruthenium particles typically have a diameter in the range of 3 to 15 microns, preferably 4.5 microns. Tantalum fibers typically have a diameter in the range of 80 to 500 nanometers and a length in the range of 20 to 300 micrometers. The columnar particles typically have a diameter in the range of 15 to 25 microns and a column height in the range of 1 to 4 microns. In addition to using ruthenium as the active material, the cohesive material may also be included in a mixture of other active materials, such as graphite or hard carbon and/or conductive materials such as carbon black, acetylene black or ketjen black.

矽 is preferably a less expensive ruthenium which has problems with the NaCMC discussed above; such ruthenium typically has a purity of less than 99.800%, although the surface area of ruthenium also appears to have an effect on the level of impurities that cause electrode deterioration. However, the purity should generally be greater than 95.00% by mass to ensure that sufficient ruthenium is inserted into the lithium and the purity is preferably greater than 98%. The crucible can include a wide variety of impurities, primarily iron, aluminum, calcium, titanium, phosphorus, boron, and/or carbon, each present in an amount of up to about 0.2%.

The ruthenium particles used to prepare the ruthenium fibers and the columnar particles used in the manufacture of the electrode of the present invention may be in the form of a crystal, such as a mono- or poly-crystal form. The polymorphic particles may comprise any number of crystals, such as two or more.

It will be understood that the electrode of the first aspect of the invention comprises a cohesive material other than a current collector comprising an active material, a binder and, if desired, a conductive material. It should be understood that the term "active material" means (in the context of a lithium ion battery) a material that is capable of incorporation of lithium and release of lithium from its structure during the charge and discharge cycles of the battery. Preferably, the crucible comprises from 20 to 100% of the active material in the cohesive material. Other active materials can be added. Suitable active materials include graphite and hard carbon. In a first embodiment of the electrode of the first aspect of the invention, the active material comprises from 20 to 100% bismuth and from 0 to 80% of activated carbon selected from the group consisting of graphite and/or hard carbon.

The cohesive material suitably comprises from 50 to 95% active material, preferably from 60 to 90%, and especially from 70 to 80%.

The binder of Table 1 can be used in a mixture with other binders and should constitute at least 10% by weight, preferably at least 25% by weight, and the binder of Table 1 can optionally comprise at least 90% by weight of the total of the electrodes. Adhesive content. Particular mention should be made of a combination of poly(acrylic acid) (PAA) / carboxymethyl cellulose (CMC) and a combination of PAA and polyvinylidene fluoride (PVDF).

The cohesive material suitably comprises from 5 to 20% by weight of binder, preferably from 8 to 15% by weight, and especially from 8 to 12% by weight of binder. The best content is 12% binder.

As indicated above, the cohesive material may optionally comprise a conductive material. Examples of suitable electrically conductive materials include carbon black, acetylene black, kettering black, channel black, and conductive fibers such as carbon fibers (including carbon nanotubes). The cohesive material suitably comprises from 10 to 30% of electrically conductive carbon, preferably from 8 to 20%, and especially from 12 to 14%.

Special description of preferred specific examples

Example 1 - Preparation of Electrode and Testing of Adhesive

A range of binders are made by using tantalum powder as the active material, the binder as stated in Table 2, and conductive carbon black (Super P from TIMCAL, Strada Industriale, CH-6743 Bodio, Switzerland). Carbon black, or Denka Black obtained from Denka (Denki Kagaku Kogyo Kabushiki Kaisha, Tokyo), or a mixture thereof, is an active material of 80:8:12 (% by weight) or 76:12:12 (% by weight): Adhesive: The anode assembled by the ratio of carbon black was tested. The polymer solution is pre-formed by dissolving the polymeric solid material in a suitable solvent (water or organic solvent, as set forth in Table 2). The special composite mixture was started with a relative weight % of the Si active material dispersed by shearing for 12 hours to 10-15% by weight of bead milled carbon black (Super P carbon or Denka Black) solution. A relative weight percent polymer solution was then added thereto and the resulting composite was subjected to a Dual Asymmetric Centrifugation dispersion for 20 minutes.

Alternatively, the carbon black can be dispersed into the polymer solution by shear stirring. The tantalum material is then added to the polymer/carbon mixture in another shear agitation step.

The resulting mixture was deposited on a copper foil substrate with a thin wet down film using a draw down blade. The deposited film is left to dry (preferably on a hot plate of 50 to 70 ° C), so that all the solvent (water or organic solvent) is removed, leaving a dry composite electrode attached to the copper foil substrate, which serves as a battery pack Current collector in the battery.

The bismuth active material used to test the composition of the binder is one of: (a) 矽 powder J230 from Elkem, Norway, having an average particle size of 4.5 microns, or (b) columnar particles (in the table) 2 is referred to as 〝PP〞), which is prepared according to the procedure disclosed in WO 2009/010758, or (c) fiber (referred to as 〝F+〞 in Table 2), which is formed from columnar particles. The column of nuclear separation into columnar particles is as disclosed in WO 2009/010758.

Jetmilled Silgrain from batch analysis The chemical analysis records of HQ (used as the starting material for the preparation of columnar particles and fibers, as described in WO 2009/010758 and also the brand of J230 material) are as follows:

A composite electrode comprising ruthenium, a polymer binder material and carbon is incorporated into a lithium metal counter electrode, a microporous separation plate, and a lithium hexafluorophosphate having a 1.2 m/m3 mixture in a mixture of ethylene carbonate/ethyl methyl carbonate. The form of electrolyte in the battery. An individual sample of a dry composite electrode (containing ruthenium, polymer, and carbon) of about 15 square centimeters was assembled in a water-free environment with metal lithium of a similar size, with a microporous separation plate disposed therebetween. The battery structure is immersed in the electrolyte solution prior to heat sealing in the aluminum laminate packaging material such that the composite electrode and the metallic lithium counter electrode are externally connected via the two ends. The first cycle loss (FCL) of the battery was tested by measuring the difference between the charge and discharge capacity (product of current and time) of the first charge/discharge cycle of the battery.

The number of possible reversible charge/discharge/cycles is recorded on a computer controlled battery test station before the battery capacity reaches less than 50% of the initial charge capacity. The computer measures the charge and discharge capacity per cycle and measures the number of cycles at a discharge capacity of less than 50% of the maximum discharge capacity. A summary of the results is presented in Table 2:

The abbreviations used in Table 2 are stated in Table 3:

As can be seen in Table 2, PAA binders provide first cycle losses (FCL) and lifetime (in terms of cycle number) over other binders, especially in NMP solvents.

All lithium ion batteries have some first cycle losses. An FCL value of >20% indicates that the binder does not maintain electrical contact between the ruthenium particles and the copper current collector because the ruthenium particles expand and contract.

Some tests used 74:13:13 active material (Si): binder: carbon ratio (in % by weight), polymer binder NaCMC (using water-based solvent) and PAA (using water and Both organic solvents), and such composite anodes produced a first cycle loss in the range of 8-9% FCL.

Example 2 - Measuring the first cycle loss

Using the same battery structure and manufacturing method as in Example 1, a battery having various binders of Izumi 2 was formed and the FCL was tested. The FCL test results of various binders are shown in the bar graph of Fig. 2. It should be noted that Table 2 includes a wide variety of experiments including different composition ratios (such as 74:13:13), whereas Figure 2 is based on a standard formulation of 80:8:12.

Example 3

Using the same battery structure and manufacturing method as in Example 1, a battery having various binders of Izumi 2 was formed and the battery was tested to find out the effect of the anode binder on the cycle capacity and the results are shown in the strip of FIG. In the picture. Figure 3 shows the total delithiation capacity of a tantalum composite electrode having a lithium metal counter electrode. The total delithiation capacity is the lithium capacity in milliamperes from the test sample cell associated with the electrochemical step, corresponding to the discharge in a true Li-ion battery (i.e., where lithium is removed from the tantalum material). The total delithiation capacity is the cumulative amount of capacity from all cycles up to the point at which the test cell appears to be ineffective.

Lithium metal electrodes have a limited cycle life because of the porous and uneven deposits that are formed when aluminum is electroplated onto the anode during charging. Typically, the total capacity of a standard battery configuration can be 500-600 milliampere hours before the lithium electrode fails. Therefore, if the capacity is >500 mAh, the battery has failed because the lithium metal is opposite the electrode. However, if the capacity is <500 mAh, the battery has failed because of the powder composite electrode. Therefore, most of the adhesive does not allow the battery to fully circulate.

Example 4

Using the same battery structure and manufacturing method as in Example 1, a battery having various binders was formed using the solvent of Izumi 2 and the battery was tested to find out the effect of the binder on the cycle capacity of the battery.

The results are shown in Figure 4, which shows the use of four different types of binders: PVDF, SBR, NaCMC and PAA of Silgrain Delithiation capacity of HQ J230 tantalum composite electrode. The lithiation capacity of the first cycle was limited to 1200 milliampere-hours per gram based on the weight of the tantalum powder in the electrode. Lithiumization in subsequent cycles is limited by charging and/or voltage limits.

As explained above, the cycling of these cells is ultimately limited by the lithium metal opposing electrode. However, it is clear that batteries with both PVDF and SBR are more susceptible to capacity loss before the lithium metal counter electrode is compromised.

Example 5

Various batteries were made using the following method: The active material was applied to a copper substrate to form an anode and the assembly was dried as described in Example 1. The cathode material used in the battery is a commercially available standard cathode material and is used with an aluminum current collector. The anode and cathode of the desired size were cut and then dried overnight at 120 ° C under dynamic vacuum. The appendix to ultrasonic welding to the anode and the cathode, allowing the battery sealed in an aluminum laminate bag, and then the electrode layer with a porous polyethylene separator in Tonen ^TM fit between their plates, wound into a roll and is arranged in the stack In the layer bag. The battery is wound in a bag and left in an unsealed edge to allow electrolyte filling.

The battery was filled under a partial vacuum with the desired electrolyte weight. The electrolyte was 1 M LiPF ₆ in 3:7 EC (ethylene carbonate): EMC (ethyl methyl carbonate). The electrolyte was allowed to soak in the electrode for 1 hour and then the last edge of the bag was vacuum sealed.

The battery is connected to the battery pack Arbin ^TM circulation device and with the continuous charging and discharging cycle test. The test mode uses a capacity limit, an upper voltage limit at the time of charging, and a lower voltage limit at the time of discharge. Charge the battery to a capacity of up to 1200 mAh/g.

A series of binders were tested by assembling the anodes using the above method; the active anode material was J230 tantalum powder (sold by one of the Silgrain HQ products from Elkem, Norway), and the binders and conductive carbons listed in Table 4 Black (Super P Carbon black), with the active material (A) stated in Table 4: Adhesive (B): Super P Carbon (C) ratio. Table 4 also states the cathodes used in the various tests, where 〝MMO〞 represents a mixed metal oxide (especially Li _1+x Ni _0.8 Co _0.15 Al _0.05 O ₂ , where 0<x< ₁ , _0.05 <x< 0.1) Cathodes and 〝LCO〞 represent lithium cobalt oxide (LiCoO ₂ ) cathodes, both of which are well known and commercially available.

The abbreviations in Table 4 are set forth in Table 5.

Figure 5 shows the effect of different binders on discharge capacity during a fixed charge/discharge cycle. As can be seen, PAA adhesives provide substantially better discharge capacity maintenance than the adhesives used in other batteries.

Example 6 - Tantalum fiber

The binder was tested by assembling the anode using the method of Example 5, except that the enamel fibers prepared by the method set forth in WO 2007/083152 or WO 2007/083155 were used instead of the tantalum powder. These fibers typically have a diameter in the range of 80 to 500 nanometers and a length in the range of 20 to 300 micrometers. The binders and various variations in the battery are set forth in Table 6.

The abbreviations in Table 6 are set forth in Table 7.

Figure 6 shows the effect of different binders on discharge capacity during a fixed charge/discharge cycle. As can be seen, PAA adhesives provide substantially better discharge capacity maintenance than the adhesives used in other batteries.

Example 7 - 矽 powder particles

The binder was tested by assembling the anode using the method of Example 5, except that the crucible instead of the crucible had the form of columnar particles prepared according to the method set forth in WO 2009/010758 (which had a range of 15 to 25 microns) Outside the diameter and column height in the range of 1 to 4 microns). The binders and various variations in the battery are set forth in Table 8.

Figure 7 shows the effect of different binders on discharge capacity during a fixed charge/discharge cycle. As can be seen, PAA adhesives provide substantially better discharge capacity maintenance than the adhesives used in other batteries.

10‧‧‧ Copper Current Collector

12‧‧‧Aluminum Current Collector

14‧‧‧Febricated composite anode layer

16‧‧‧Composite cathode layer based on lithium-containing metal oxides

20‧‧‧Porous plastic partition or divider

1 is a graphical representation of a lithium ion battery; and FIGS. 2-7 are graphs showing the results of Examples 2-7.

10. . . Copper current collector

12. . . Aluminum current collector

14. . . Graphite-based composite anode layer

16. . . Composite cathode layer based on lithium-containing metal oxide

20. . . Porous plastic partition or divider

Claims (12)

An electrode for a lithium ion rechargeable battery cell, comprising: a current collector, and a cohesive material comprising ruthenium as an active material and a polymerizable binder, wherein the polymerizable binder is one or a homopolymer or copolymer of a plurality of monomers selected from the group consisting of acrylic acid, 3-butenoic acid, 2-methacrylic acid, 2-pentenoic acid, 2,3- Dimethacrylic acid, 3,3-dimethacrylic acid, trans-butenedioic acid, cis-butenedioic acid and itaconic acid, and optionally an alkali metal salt thereof, wherein cerium contains 20 to 100% active A material, and wherein the binder is mixed with the crucible to form a cohesive material that adheres to the current collector and maintains the cohesive material in electrical contact with the current collector. The electrode according to claim 1, wherein the bismuth material constitutes at least 50% by weight of the active material in the electrode; and the polymerizable binder is taken from one of the following: And a copolymer thereof, wherein the above polymer constitutes a majority of monomer units mixed with a ruthenium material (for example, particles, fibers, structoids or columnar particles) to form a cohesive material It is attached to the current collector and maintains the material in electrical contact with the current collector. The electrode according to claim 1 or 2, wherein the polymerizable binder is polyacrylic acid having a molecular weight of more than 50,000, for example, more than 450,000. The electrode according to claim 1, wherein the crucible has a purity of 95 to 99.90% by weight, for example 98 to 99.0% by weight. The electrode according to claim 1, 2 or 4, wherein the binder comprises one or more of the polymer and another binder, such as an elastomer such as carboxymethyl cellulose (CMC) and/or a mixture of polyvinylidene fluoride. The electrode according to claim 1, 2 or 4, wherein the cohesive material comprises a conductive reinforcing material such as carbon black and/or acetylene black. An electrode according to the first, second or fourth aspect of the patent application is an anode. The electrode according to claim 1, 2 or 4, wherein the bismuth material is in the form of particles, fibers, ribbons or columnar particles. The electrode according to claim 1, 2 or 4, wherein the bismuth material comprises 20 to 100% by weight, for example at least 50% by weight, preferably at least 70% by weight, and optionally 100% by weight, in the electrode. Active material. The electrode according to claim 1, 2 or 4, wherein the active material further comprises activated carbon selected from the group consisting of graphite and/or hard carbon. A lithium ion battery comprising the electrode as claimed in any one of claims 1 to 10. A device comprising the electrode according to any one of claims 1 to 10 or the lithium ion battery according to claim 11 of the patent application.